Method of tracking fluids produced from various zones in subterranean wells

ABSTRACT

Compositions and methods for determining the source of treatment fluids being produced from a production formation having multiple zones.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of copending U.S.patent application Ser. No. 10/125,17 1, filed Apr. 18, 2002, the entiredisclosure of which is incorporated herein by reference.

BACKGROUND

[0002] The present embodiment relates generally to the recovery ofhydrocarbons from a subterranean formation penetrated by a well bore andmore particularly to non-radioactive compositions and methods ofutilizing the non-radioactive compositions for determining the source oftreatment fluids being produced from a production formation havingmultiple zones. For example, the compositions and methods can beutilized for tracking the transport of particulate solids during theproduction of hydrocarbons from a subterranean formation penetrated by awell bore.

[0003] Transport of particulate solids during the production ofhydrocarbons from a subterranean formation penetrated by a well bore isa continuing problem. The transported solids can erode or causesignificant wear in the hydrocarbon production equipment used in therecovery process. The solids also can clog or plug the well bore therebylimiting or completely stopping fluid production. Further, thetransported particulates must be separated from the recoveredhydrocarbons adding further expense to the processing. The particulateswhich are available for transport may be present due to anunconsolidated nature of a subterranean formation and/or as a result ofwell treatments placing particulates in a well bore or formation, suchas, by gravel packing or propped fracturing.

[0004] In the treatment of subterranean formations, it is common toplace particulate materials as a filter medium and/or a proppant in thenear well bore area and in fractures extending outwardly from the wellbore. In fracturing operations, proppant is carried into fracturescreated when hydraulic pressure is applied to these subterranean rockformations to a point where fractures are developed. Proppant suspendedin a viscosified fracturing fluid is carried outwardly away from thewell bore within the fractures as they are created and extended withcontinued pumping. Upon release of pumping pressure, the proppantmaterials remain in the fractures holding the separated rock faces in anopen position forming a channel for flow of formation fluids back to thewell bore.

[0005] Proppant flowback is the transport of proppants back into thewell bore with the production of formation fluids following fracturing.This undesirable result causes undue wear on production equipment, theneed for separation of solids from the produced hydrocarbons andoccasionally also decreases the efficiency of the fracturing operationsince the proppant does not remain within the fracture and may limit thewidth or conductivity of the created flow channel.

[0006] Current techniques for controlling the flowback of proppantsinclude coating the proppants with curable resin, or blending theproppants with fibrous materials, tackifying agents or deformableparticulates (See e.g. U.S. Pat. No. 6,328,105 to Betzold, U.S. Pat. No.6,172,011 to Card et al. and U.S. Pat. No. 6,047,772 to Weaver et al.)For a multi-zone well that has been fractured with proppant and isplagued with proppant flowback problems, it is quite difficult toidentify the zone from which the proppant is emanating unless theproppant is tagged with a tracer. Radioactive materials have beencommonly used in the logging or tagging of sand or proppant placement,however, such radioactive materials are hazardous to the environment andthe techniques for utilizing such radioactive materials are complex,expensive and time consuming. Therefore, there is a need for simplecompositions and methods for tracking the flowback of proppant insubterranean wells to avoid the above problems.

DETAILED DESCRIPTION

[0007] According to one embodiment, to determine from which zone(s) afluid is being produced, a water soluble inorganic or organic salt isdissolved in the base treatment fluid as the fluid is being pumpeddownhole during the treatment. Such treatment fluids include but are notlimited to fracturing fluids, drilling fluids, disposal fluids andinjection fluids used as displacement fluids in hydrocarbon recoveryprocesses. Acting as a fluid tracer agent, a salt is tagged into thefluid that is unique for each treatment job such as a fracturing jobtreatment. Suitable water soluble salts for this purpose are metal saltsin which the metal is selected from Groups I to VIII of the PeriodicTable of the Elements as well as the lanthanum series rare earth metalsso long as the metal salts do not constitute a component of fluidsnaturally present in the formation and are compatible with the fluidsinjected into the formation. Preferred metals include barium, beryllium,cadmium, chromium, cesium, sodium, potassium, manganese and zinc.Particularly preferred water soluble salts include barium bromide,barium iodide, beryllium fluoride, beryllium bromide, berylliumchloride, cadmium bromide, cadmium chloride, cadmium iodide, cadmiumnitrate, chromium bromide, chromium chloride, chromium iodide, cesiumbromide, cesium chloride, sodium bromide, sodium iodide, sodium nitrate,sodium nitrite, potassium iodide, potassium nitrate, manganese bromide,manganese chloride, zinc bromide, zinc chloride, zinc iodide, sodiummonofluoroacetate, sodium trifluoroacetate, sodium 3-fluoropropionate,potassium monofluoroacetate, potassium trifluoroacetate, potassium3-fluoropropionate.

[0008] The fluid tracer agents used in the method of this embodimentmust meet a number of requirements. They should be relativelyinexpensive, must be compatible with fluids naturally present in thereservoir and within the rock itself, as well as be compatible with thefluids injected into the reservoir as part of the formation treatment.The fluid tracer agents must be susceptible to being readily detectedqualitatively and analyzed quantitatively in the presence of thematerials naturally occurring in the formation fluids. For example, anaqueous sodium chloride solution could be utilized as a fluid traceragent but for the fact that most field brines contain sodium chloride insubstantial quantities, and so detection and analysis to differentiatethe presence of sodium chloride used as tracer in the presence ofnaturally-occurring sodium chloride would be difficult.

[0009] In field application, a known amount of a selected water solublesalt based on a known concentration (i.e. 100 parts per million) isdissolved in a volume of water which is 1/1,000 of the total actualvolume of base fluid required for the treatment. The mixed solution isthen metered to the base fluid line at a rate of one gallon per 1,000gallons of the base fluid. To handle multiple zones, various salts canbe used provided that the interest cations or anions of selectedcompounds are unique to prevent any interference between zones.

[0010] According to another embodiment, metals are tagged onto proppantmaterial or materials to be blended with proppant material to providefor the ready identification of flowback proppant from different stagesor zones of the well. Suitable metals for this purpose may be selectedfrom Groups I to VIII of the Periodic Table of the elements as well asthe lanthanum series rare earth metals so long as the metals do notconstitute a component of the proppant, the fracturing fluid or thereservoir fluid and so long as the metals are compatible with thefracturing fluid. Preferred metals include gold, silver, copper,aluminum, barium, beryllium, cadmium, cobalt, chromium, iron, lithium,magnesium, manganese, molybdenum, nickel, phosphorus, lead, titanium,vanadium and zinc as well as derivatives thereof including oxides,phosphates, sulfates, carbonates and salts thereof so long as suchderivatives are only slightly soluble in water so that they remainintact during transport with the proppant from the surface into thefractures. Particularly preferred metals include copper, nickel, zinc,cadmium, magnesium and barium. The metal acts as a tracer material and adifferent metal is tagged onto the proppant, or onto the materials to beblended with the proppant, so that each proppant stage or eachfracturing job treatment can be identified by a unique tracer material.Suitable metals for use as the tracer material are generallycommercially available from Sigma-Aldrich, Inc. as well as fromMallinckrodt Baker, Inc. It is understood, however, that field gradematerials may also be used as suitable tracer materials for tagging ontoproppant material or materials to be blended with proppant material.

[0011] Samples of flowback proppant collected from the field may beanalyzed according to a process known as the inductively-coupled plasma(ICP) discharge method to determine from which proppant stage and whichproduction zone the proppant has been produced. According to the ICPdischarge method, an aqueous sample is nebulized within an ICPspectrometer and the resulting aerosol is transported to an argon plasmatorch located within the ICP spectrometer. The ICP spectrometer measuresthe intensities of element-specific atomic emissions produced when thesolution components enter the high-temperature plasma. An on-boardcomputer within the ICP spectrometer accesses a standard calibrationcurve to translate the measured intensities into elementalconcentrations. ICP spectrometers for use according to the ICP dischargemethod are generally commercially available from the Thermo ARL businessunit of Thermo Electron Corporation, Agilent Technologies and severalother companies. Depending upon the model and the manufacturer, thedegree of sensitivity of currently commercially available ICPspectrometers can generally detect levels as low as 1 to 5 parts permillion for most of the metals listed above.

[0012] It is understood that depending on the materials used as taggingagents, other spectroscopic techniques well known to those skilled inthe art, including atomic absorption spectroscopy, X-ray fluorescencespectroscopy, or neutron activation analysis, can be utilized toidentify these materials.

[0013] According to yet another embodiment, an oil-soluble oroil-dispersible tracer comprising a metal salt, metal oxide, metalsulfate, metal phosphate or a metal salt of an organic acid can be usedto tag the proppant by intimately mixing the metal with a curable resinprior to coating the curable resin onto the proppant. Preferably, themetal is selected from the Group VIB metals, the Group VIIB metals, andthe lanthanum series rare earth metals. Specifically, the metalaccording to this embodiment may be chromium, molybdenum, tungsten,manganese, technetium, rhenium, lanthanum, cerium, praseodymium,neodymium, promethium, samarium, europium, gadolinium, terbium,dysprosium, holmium, erbium, thulium, ytterbium and lutetium. It ispreferred that the metals according to this embodiment, do notconstitute a component of the proppant, the fracturing fluid or thereservoir fluid, and that the metals are compatible with the fracturingfluid.

[0014] Preferably, the organic acid is a substituted or unsubstitutedcarboxylic acid. More preferably, the organic acid may be selected fromalkanoic and alkenoic carboxylic acids, polyunsaturated aliphaticmonocarboxylic acids and aromatic carboxylic acids. Most preferably, thealkanoic carboxylic acids have from 5 to 35 carbon atoms, the alkenoiccarboxylic acids have from 5 to 30 carbon atoms, the polyunsaturatedaliphatic monocarboxylic acids may be selected from the group of sorbic,linoleic, linolenic, and eleostearic acids and the aromatic acids may beselected from the group of benzoic, salicylic, cinnamic and gallicacids. Suitable organic acids are generally commercially available fromSigma-Aldrich, Inc. as well as from Mallinckrodt Baker, Inc.

[0015] For proppant to be coated with a curable resin, the tracer agentis blended homogeneously with the resin mixture and the resin is thencoated onto the proppant. The proppant can be pre-coated as in the caseof curable resin-coated proppants, for example, such as thosecommercially available from Santrol or Acme Borden, or it can be coatedon-the-fly during the fracturing job treatment. The nature of the resinmaterials and the processes for performing the coating process is wellknow to those skilled in the art, as represented by U.S. Pat. No.5,609,207 to Dewprashad et al., the entire disclosure of which is herebyincorporated herein by reference. Also, it is understood that materialsto be blended with proppant such as the fibrous materials, tackifyingagents or deformable beads disclosed in U.S. Pat. No. 6,328,105 toBetzold, U.S. Pat. No. 6,172,011 to Card et al. and U.S. Pat. No.6,047,772 to Weaver et al., the entire disclosures of which are herebyincorporated by reference, can be similarly treated with a tracer agent.

[0016] According to still another embodiment, the metal elements ortheir derivative compounds can be tagged as part of the manufacturingprocess of proppant. As a result, the proppant is tagged with apermanent tracer.

[0017] According to yet another embodiment, the proppant can be coatedwith phosphorescent, fluorescent, or photoluminescent pigments, such asthose disclosed in U.S. Pat. No. 6,123,871 to Carroll, U.S. Pat. No.5,498,280 to Fistner et al. and U.S. Pat. No. 6,074,739 to Katagiri, theentire disclosures of which are hereby incorporated herein by reference.According to this embodiment, the phosphorescent, fluorescent, orphotoluminescent pigments may be prepared from materials well known tothose skilled in the art including but not limited to alkaline earthaluminates activated by rare earth ions, zinc sulfide phosphors,aluminate phosphors, zinc silicate phosphors, zinc sulfide cadmiumphosphors, strontium sulfide phosphors, calcium tungstate phosphors andcalcium sulfide phosphors. Suitable phosphorescent, fluorescent andphotoluminescent materials are commercially available from KeystoneAniline Corporation (TB Series) and Capricorn Chemicals (H Series and SSeries Glowbug Specialty Pigments). The particular structure of thematerials has a strong capacity to absorb and store visible light suchas sunlight or light from artificial lighting. After absorbing a varietyof such common visible light the phosphorescent, fluorescent, orphotoluminescent materials will glow in the dark. Various pigment colorscan be combined with the luminescent capability of the materials toenhance the differentiation of the stages or zones. According to thisembodiment, micron sized particles of the phosphorescent, fluorescent,or photoluminescent materials are intimately mixed with a resin to becoated onto a proppant to be used in a fracturing treatment.

[0018] According to still another embodiment, proppant materials havinga naturally dark color can be dyed or coated with a marker materialhaving a bright, vivid and intense color which marker material may beselected from oil soluble dyes, oil dispersible dyes or oil dispersiblepigments. Suitable oil soluble dyes, oil dispersible dyes and oildispersible pigments are well known to those skilled in the art and aregenerally commercially available from Keystone Aniline Corporation andAbbey Color. According to this embodiment, proppant materials having adark color, such as bauxite proppant which is naturally black in color,are dyed or coated with such marker materials. In this regard, referenceis made to the dyes disclosed in U.S. Pat. No. 6,210,471 to Craig, theentire disclosure of which is hereby incorporated herein by reference.

[0019] According to all of the above-described embodiments, the proppantmaterial may comprise substantially any substrate material that does notundesirably chemically interact with other components used in treatingthe subterranean formation. It is understood that the proppant materialmay comprise sand, ceramics, glass, sintered bauxite, resin coated sand,resin beads, metal beads and the like.

[0020] The following examples are illustrative of the methods andcompositions discussed above.

EXAMPLE 1

[0021] ZnCl₂ was selected to tag 50,000 gallons of a base fracturingfluid. For a 100-ppm concentration of ZnCl₂ in the fracturing fluid, itrequires 0.2084 gram per liter of fluid, or 39.44 kg for the total fluidvolume. This amount of ZnCl₂ is dissolved in 50 gallons of fluid, andthe mixed solution is metered into the base fluid line at a rate of 1gallon for every 1,000 gallons of the base fluid.

[0022] A number of methods well known to those of ordinary skill in theart such as wet chemistry titration, colorimetry, atomic absorptionspectroscopy, inductively coupled plasma (ICP) discharge, ionchromatography (IC), gas chromatography (GC), liquid chromatography (LC)and nuclear magnetic resonance (NMR), can be used to analyze the fluidsamples produced from the well and to determine from which zones thefluid has been produced, and the theoretical production level of eachzone in the well.

EXAMPLE 2

[0023] A total of three separate hydraulic fracturing treatments wereperformed in a subterranean formation penetrated by a well bore. Foreach fracturing treatment, sufficient metal tracer was added to theliquid hardenable resin to provide an initial concentration of 1000 ppmof the metal tracer in the resin treated proppant. Cuprous oxide,manganese oxide, and zinc oxide were used as tagging agents infracturing treatments 1, 2, and 3, respectively. Samples of flowbackproppant were collected during the flow back of the well. Each proppantsample was weighted and digested in concentrated nitric acid beforebeing measured against known, calibrated metal concentrations accordingto the inductively coupled plasma (ICP) discharge method for the ARLModel 3410 ICP which is commercially available from the Thermo ARLbusiness unit of Thermo Electron Corporation. Table 1 shows theconcentrations of each metal obtained in each proppant flowback sample.The data indicated that the highest concentration of flowback proppantwas produced from the interval of the well that was fractured in thesecond fracturing treatment. TABLE 1 Sample Frac Treatment 1 FracTreatment 2 Frac Treatment 3 Number Cu (ppm) Mn (ppm) Zn (ppm) 1 1.9217.3 11.5 2 2 219.2 11.8 3 2.8 120.5 9.1 4 3.1 204.1 12 5 670.6 38224.1 6 51.6 214.1 15.3 7 7.3 234.5 13.3 8 2.7 437.7 17.1 9 2.3 183.811.9 10 2.7 220.2 12.8 11 2.9 465 19.3 12 2.1 408.1 17.4 13 2.7 577.219.3 14 3.1 410.2 18.2 15 2.3 342.9 40.2 16 2.1 299.8 14.9 17 6.5 296.812.5 18 2.1 494.8 18 19 51 385.8 16.5 20 2.7 443.8 17 21 2.8 564.8 44.622 35.5 551.8 16.1 23 2.4 545.8 23.3 24 2 538.8 14.7 25 181 342.8 16.626 1.5 119.8 10.3 27 1.4 34.8 11.9 28 1.9 204.8 43.2 29 2 240.8 13.7 302.4 175.8 11.3 31 7.5 171.8 10.9 32 2.3 57.8 7.7 33 5.8 192.8 17 34 1.7188.8 12.1 35 1.9 115.8 9.6 36 2.1 168.9 11.1 37 1.6 245.3 13 38 1.7173.9 11.6 39 1.9 219.4 12.9 40 1.9 224.6 12.6 41 2 383.3 17.1 42 1.7284.7 12.5 43 1.9 270.6 13.4 44 2.4 311 12.7 45 1.9 177.1 10.3 46 1.8304.2 12.9 47 2.4 343.2 13.3 48 2 308.2 12.6 49 5.4 241.6 11.2 50 3.4209.1 11.4 51 3.3 217.1 11.1 52 1.9 299.7 12.7 53 2.3 228.6 11.4 54 1.5162.8 10.1

EXAMPLE 3

[0024] A total of five separate hydraulic fracturing treatments wereperformed in a subterranean formation by a well bore. For eachfracturing treatment, sufficient metal tracer was added to the liquidhardenable resin to provide an initial concentration of 1000 ppm of themetal tracer in the resin treated proppant. Manganese oxide, cuprousoxide, zinc oxide, magnesium oxide, and barium oxide were used astagging agents in fracturing treatments 1 through 5, respectively.Samples of flowback proppant were collected during the flow back of thewell. Each proppant sample was weighted and digested in concentratednitric acid before being measured against known, calibrated metalconcentrations according to the inductively coupled plasma (ICP)discharge method for the ARL Model 3410 ICP which is commerciallyavailable from the Thermo ARL business unit of the Thermo ElectronCorporation. Table 2 shows the concentrations of each metal obtained ineach proppant flowback sample. The data indicated that the highestconcentration of flowback proppant was produced from the intervals ofthe well that were fractured in fracturing treatments 1 and 5. TABLE 2Frac Frac Frac Frac Frac Treatment Treatment Treatment TreatmentTreatment Sample 1 2 3 4 5 Number Mn (ppm) Cu (ppm) Zn (ppm) Mg (ppm) Ba(ppm) 1 256.9 7.3 18.2 26.8 106.2 2 210.3 14.5 23.1 24 110.6 3 164.512.4 20.2 22.5 94.8 4 236.5 9.1 19.9 23.3 100.4 5 97.8 10.5 14.7 19105.7 6 288.9 2.8 15.8 25.4 110.4 7 202.8 172.8 12.1 21.3 99.7 8 221.3 312.8 22.3 115.9 9 167.9 2.9 12.5 21.8 115.7 10 236.1 2.2 12.5 22.8 90.711 162.6 1.6 10.8 19.5 85.9 12 111.8 1.6 8.9 18.8 74.9 13 231.8 1.7 11.521.7 86.7 14 246.9 2.5 13.1 24.4 98.3 15 348.2 2 13.5 26.8 112.8 16273.5 2.4 12.4 24.4 101 17 221.5 2 11.4 29.3 83.8 18 268 1.4 11.9 25.888.4 19 177.8 1.8 10.4 22.3 77.8 20 247.5 2.4 11.3 28 92.2 21 132.8 1.810 22.2 72.4 22 165.8 2.3 9.4 20.9 75.3 23 306.9 66.4 11.9 28.7 103.8 24205.7 1.6 9.4 23 87.1 25 241.2 2.6 10.6 23.4 90.4 26 197.6 2.2 10.1 24.188 27 242 2.3 10.7 26.2 98.9 28 202.8 3 10.8 24.6 94.6 29 165.7 2 9 20.785.5 30 138.3 1.4 8.7 21.3 76.1 31 227.4 1.5 10.3 24 92.8 32 192.1 1.79.8 23.5 86.6 33 201.9 1.2 9.6 22.3 86.4 34 138.4 1.7 8.6 19.8 73.9

[0025] Variations and Equivalents

[0026] Although only a few exemplary embodiments have been described indetail above, those skilled in the art will readily appreciate that manyother modifications are possible in the exemplary embodiments withoutmaterially departing from the novel teachings and advantages describedherein. Accordingly, all such modifications are intended to be includedwithin the scope of the following claims.

What is claimed is:
 1. A method of treating a subterranean formationhaving multiple zones penetrated by a well bore comprising: providing aplurality of treatment compositions comprising a tracking material,wherein the tracking material is selected from the group consisting ofwater soluble inorganic salts, water soluble organic salts, metals,metal salts of organic acids, phosphorescent pigments, fluorescentpigments, photoluminescent pigments, oil soluble dyes, oil dispersibledyes and oil dispersible pigments, and wherein each treatmentcomposition comprises a different tracking material; introducing adifferent treatment composition into each zone in the subterraneanformation through a well bore; flowing fluid back from the subterraneanformation whereby at least a portion of at least one of the treatmentcompositions flows back from the subterranean formation; and identifyingeach zone in which the at least one treatment composition was introducedby detecting the tracking compositions in the fluid that flows back fromthe subterranean formation.
 2. A method of treating a subterraneanformation having multiple zones penetrated by a well bore according toclaim 1, wherein the treatment composition comprises a treatment fluidselected from the group consisting of fracturing fluids, drillingfluids, disposal fluids and injection fluids.
 3. A method of treating asubterranean formation having multiple zones penetrated by a well boreaccording to claim 1, wherein the tracking material comprises a watersoluble inorganic or organic metal salt.
 4. A method of treating asubterranean formation having multiple zones penetrated by a well boreaccording to claim 3, wherein the water soluble inorganic or organicmetal salt comprises a metal selected from Groups I to VIII of thePeriodic Table of the elements and the lanthanum series rare earthmetals; provided that the metal salt is not a component of the treatmentcompositions; and provided that the metal salt is compatible with thefluids disposed within the well bore.
 5. A method of treating asubterranean formation having multiple zones penetrated by a well boreaccording to claim 4, wherein the metal is selected from the groupconsisting of barium, beryllium, cadmium, chromium, cesium, sodium,potassium, manganese and zinc.
 6. A method of treating a subterraneanformation having multiple zones penetrated by a well bore according toclaim 3, wherein the metal salt is selected from the group consisting ofbarium bromide, barium iodide, beryllium fluoride, beryllium bromide,beryllium chloride, cadmium bromide, cadmium chloride, cadmium iodide,cadmium nitrate, chromium bromide, chromium chloride, chromium iodide,cesium bromide, cesium chloride, sodium bromide, sodium iodide, sodiumnitrate, sodium nitrite, potassium iodide, potassium nitrate, manganesebromide, manganese chloride, zinc bromide, zinc chloride, zinc iodide,sodium monofluoroacetate, sodium trifluoroacetate, sodium3-fluoropropionate, potassium monofluoroacetate, potassiumtrifluoroacetate, potassium 3-fluoropropionate.
 7. A method of treatinga subterranean formation having multiple zones penetrated by a well boreaccording to claim 1, wherein the treatment composition comprises aparticulate material and a tracking material and wherein the trackingmaterial comprises a metal selected from Groups I to VIII of thePeriodic Table of the elements and the lanthanum series rare earthmetals; provided that the metal is not a component of the particulatematerial; and provided that the metal is compatible with the fluidsdisposed within the well bore.
 8. A method of treating a subterraneanformation having multiple zones penetrated by a well bore according toclaim 1, wherein the treatment composition comprises a particulatematerial and a tracking material and wherein the tracking materialcomprises a metal selected from the group consisting of gold, silver,copper, aluminum, barium, beryllium, cadmium, cobalt, chromium, iron,lithium, magnesium, manganese, molybdenum, nickel, phosphorus, lead,titanium, vanadium, zinc and oxide, phosphate, sulfate, carbonate andsalt derivatives thereof.
 9. A method of treating a subterraneanformation having multiple zones penetrated by a well bore according toclaim 8, wherein the tracking material comprises a metal selected fromthe group consisting of copper, nickel, zinc, cadmium, magnesium andbarium.
 10. A method of treating a subterranean formation havingmultiple zones penetrated by a well bore according to claim 8, whereinthe tracking material comprises a metal oxide selected from the groupconsisting of manganese oxide, cuprous oxide, zinc oxide, magnesiumoxide, and barium oxide.
 11. A method of treating a subterraneanformation having multiple zones penetrated by a well bore according toclaim 1, wherein the tracking material is selected from the groupconsisting of metal salts, metal oxides, metal sulfates, metalphosphates and metal salts of organic acids and the metal is selectedfrom the group consisting of chromium, molybdenum, tungsten, manganese,technetium, rhenium, lanthanum, cerium, praseodymium, neodymium,promethium, samarium, europium, gadolinium, terbium, dysprosium,holmium, erbium, thulium, ytterbium and lutetium.
 12. A method oftreating a subterranean formation having multiple zones penetrated by awell bore according to claim 11, wherein the tracking material comprisesa metal salt of an organic acid and the organic acid is selected fromthe group consisting of substituted and unsubstituted alkanoiccarboxylic acids, alkenoic carboxylic acids, polyunsaturated aliphaticmonocarboxylic acids and aromatic carboxylic acids.
 13. A method oftreating a subterranean formation having multiple zones penetrated by awell bore according to claim 12, wherein the organic acid comprises analkanoic carboxylic acid having from 5 to 35 carbon atoms.
 14. A methodof treating a subterranean formation having multiple zones penetrated bya well bore according to claim 12, wherein the organic acid comprises analkenoic carboxylic acid having from 5 to 30 carbon atoms.
 15. A methodof treating a subterranean formation having multiple zones penetrated bya well bore according to claim 12, wherein the organic acid comprises apolyunsaturated aliphatic monocarboxylic acid selected from the groupconsisting of sorbic acid, linoleic acid, linolenic acid and eleostearicacid.
 16. A method of treating a subterranean formation having multiplezones penetrated by a well bore according to claim 12, wherein theorganic acid comprises an aromatic acid selected from the groupconsisting of benzoic acid, salicylic acid, cinnamic acid and gallicacid.
 17. A method of treating a subterranean formation having multiplezones penetrated by a well bore according to claim 1, wherein thetracking material is selected from the group consisting ofphosphorescent pigments, fluorescent pigments and photoluminescentpigments and wherein the phosphorescent, fluorescent, andphotoluminescent pigments are prepared from materials selected from thegroup consisting of alkaline earth aluminates activated by rare earthions, zinc sulfide phosphors, aluminate phosphors, zinc silicatephosphors, zinc sulfide cadmium phosphors, strontium sulfide phosphors,calcium tungstate phosphors and calcium sulfide phosphors.
 18. A methodof treating a subterranean formation having multiple zones penetrated bya well bore according to claim 1, wherein the treatment compositioncomprises a particulate composition comprising a particulate materialand a tracking material wherein the particulate composition furthercomprises a material selected from the group consisting of fibrousmaterials, tackifying agents and deformable beads.
 19. A method oftreating a subterranean formation having multiple zones penetrated by awell bore according to claim 1, wherein the treatment compositioncomprises a particulate material and a tracking material and wherein thetracking material is blended with a resin to form a trackingmaterial-resin mixture and the particulate material is coated with thetracking material-resin mixture.
 20. A method of treating a subterraneanformation having multiple zones penetrated by a well bore according toclaim 1, wherein the treatment composition comprises a particulatematerial and a tracking material and wherein the particulate material istagged with the tracking material.
 21. A method of treating asubterranean formation having multiple zones penetrated by a well boreaccording to claim 1, wherein the tracking material in the fluid thatflows back from the subterranean formation is detected by aninductively-coupled plasma method.
 22. A method of propping multiplefractures in a subterranean formation penetrated by a well borecomprising: placing a proppant composition in each fracture in thesubterranean formation, wherein each proppant composition comprisesparticulate material and a tracking composition, and wherein eachproppant composition comprises a different tracking composition; flowingfluid back from the subterranean formation whereby at least a portion ofat least one of the proppant compositions flows back from thesubterranean formation; and identifying each fracture in which the atleast one proppant composition was placed by detecting the trackingcompositions in the fluid that flows back from the subterraneanformation.
 23. A method of propping multiple fractures in a subterraneanformation penetrated by a well bore according to claim 22, wherein thetracking composition is selected from the group consisting of metals,metal salts of organic acids, phosphorescent pigments, fluorescentpigments, photoluminescent pigments, oil soluble dyes, oil dispersibledyes and oil dispersible pigments.
 24. A method of propping multiplefractures in a subterranean formation penetrated by a well boreaccording to claim 22, wherein the tracking composition comprises ametal selected from Groups I to VIII of the Periodic Table of theelements and the lanthanum series rare earth metals; provided that themetal is not a component of the particulate material; and provided thatthe metal is compatible with the fluids disposed within the well bore.25. A method of propping multiple fractures in a subterranean formationpenetrated by a well bore according to claim 22, wherein the trackingcomposition comprises a metal selected from the group consisting ofgold, silver, copper, aluminum, barium, beryllium, cadmium, cobalt,chromium, iron, lithium, magnesium, manganese, molybdenum, nickel,phosphorus, lead, titanium, vanadium, zinc and oxide, phosphate,sulfate, carbonate and salt derivatives thereof.
 26. A method ofpropping multiple fractures in a subterranean formation penetrated by awell bore according to claim 25, wherein the tracking compositioncomprises a metal selected from the group consisting of copper, nickel,zinc, cadmium, magnesium and barium.
 27. A method of propping multiplefractures in a subterranean formation penetrated by a well boreaccording to claim 25, wherein the tracking composition comprises ametal oxide selected from the group consisting of manganese oxide,cuprous oxide, zinc oxide, magnesium oxide, and barium oxide.
 28. Amethod of propping multiple fractures in a subterranean formationpenetrated by a well bore according to claim 25, wherein the trackingcomposition is selected from the group consisting metal salts, metaloxides, metal sulfates, metal phosphates and metal salts of organicacids and the metal is selected from the group consisting of chromium,molybdenum, tungsten, manganese, technetium, rhenium, lanthanum, cerium,praseodymium, neodymium, promethium, samarium, europium, gadolinium,terbium, dysprosium, holmium, erbium, thulium, ytterbium and lutetium.29. A method of propping multiple fractures in a subterranean formationpenetrated by a well bore according to claim 26, wherein the trackingcomposition comprises a metal salt of an organic acid and the organicacid is selected from the group consisting of substituted andunsubstituted alkanoic carboxylic acids, alkenoic carboxylic acids,polyunsaturated aliphatic monocarboxylic acids and aromatic carboxylicacids.
 30. A method of propping multiple fractures in a subterraneanformation penetrated by a well bore according to claim 22, wherein thetracking composition is selected from the group consisting ofphosphorescent pigments, fluorescent pigments and photoluminescentpigments and wherein the phosphorescent, fluorescent, andphotoluminescent pigments are prepared from materials selected from thegroup consisting of alkaline earth aluminates activated by rare earthions, zinc sulfide phosphors, aluminate phosphors, zinc silicatephosphors, zinc sulfide cadmium phosphors, strontium sulfide phosphors,calcium tungstate phosphors and calcium sulfide phosphors.
 31. Atraceable treatment composition for treating a subterranean formationhaving multiple zones penetrated by a well bore comprising: a trackingmaterial, wherein the tracking material is selected from the groupconsisting of water-soluble inorganic salts, water soluble organicsalts, metals, metal salts of organic acids, phosphorescent pigments,fluorescent pigments, photoluminescent pigments, oil soluble dyes, oildispersible dyes and oil dispersible pigments.
 32. A traceable treatmentcomposition according to claim 31 wherein the treatment compositioncomprises a treatment fluid selected from the group consisting offracturing fluids, drilling fluids, disposal fluids and injectionfluids.
 33. A traceable treatment composition according to claim 31wherein the tracking material comprises a water soluble inorganic ororganic metal salt.
 34. A traceable treatment composition according toclaim 33 wherein the water soluble inorganic or organic metal saltcomprises a metal selected from Groups I to VIII of the Periodic Tableof the elements and the lanthanum series rare earth metals; providedthat the metal salt is not a component of the treatment compositions;and provided that the metal salt is compatible with the fluids disposedwithin the well bore.
 35. A traceable treatment composition according toclaim 34 wherein the metal is selected from the group consisting ofbarium, beryllium, cadmium, chromium, cesium, sodium, potassium,manganese and zinc.
 36. A traceable treatment composition according toclaim 33 wherein the metal salt is selected from the group consisting ofbarium bromide, barium iodide, beryllium fluoride, beryllium bromide,beryllium chloride, cadmium bromide, cadmium chloride, cadmium iodide,cadmium nitrate, chromium bromide, chromium chloride, chromium iodide,cesium bromide, cesium chloride, sodium bromide, sodium iodide, sodiumnitrate, sodium nitrite, potassium iodide, potassium nitrate, manganesebromide, manganese chloride, zinc bromide, zinc chloride, zinc iodide,sodium monofluoroacetate, sodium trifluoroacetate, sodium3-fluoropropionate, potassium monofluoroacetate, potassiumtrifluoroacetate, potassium 3-fluoropropionate.
 37. A traceabletreatment composition according to claim 31, wherein the treatmentcomposition is a proppant composition comprising a particulate materialand a tracking material and wherein the tracking material comprises ametal selected from Groups I to VIII of the Periodic Table of theelements and the lanthanum series rare earth metals; provided that themetal is not a component of the particulate material; and provided thatthe metal is compatible with the fluids disposed within the well bore.38. A traceable treatment composition according to claim 31, wherein thetreatment composition is a proppant composition comprising a particulatematerial and a tracking material and wherein the tracking materialcomprises a metal selected from the group consisting of gold, silver,copper, aluminum, barium, beryllium, cadmium, cobalt, chromium, iron,lithium, magnesium, manganese, molybdenum, nickel, phosphorus, lead,titanium, vanadium, zinc and oxide, phosphate, sulfate, carbonate andsalt derivatives thereof.
 39. A traceable treatment compositionaccording to claim 38, wherein the tracking material comprises a metaloxide selected from the group consisting of copper, nickel, zinc,magnesium and barium.
 40. A traceable treatment composition according toclaim 38, wherein the tracking material comprises a metal oxide selectedfrom the group consisting of manganese oxide, cuprous oxide, zinc oxide,magnesium oxide, and barium oxide.
 41. A traceable treatment compositionaccording to claim 31, wherein the treatment composition is a proppantcomposition comprising a particulate material and a tracking materialand wherein the tracking material is selected from the group consistingof metal salts, metal oxides, metal sulfates, metal phosphates and metalsalts of organic acids and the metal is selected from the groupconsisting of chromium, molybdenum, tungsten, manganese, technetium,rhenium, lanthanum, cerium, praseodymium, neodymium, promethium,samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium,thulium, ytterbium and lutetium.
 42. A traceable treatment compositionaccording to claim 41, wherein the tracking material comprises a metalsalt of an organic acid and the organic acid is selected from the groupconsisting of substituted and unsubstituted alkanoic carboxylic acids,alkenoic carboxylic acids, polyunsaturated aliphatic monocarboxylicacids and aromatic carboxylic acids.
 43. A traceable treatmentcomposition according to claim 42, wherein the organic acid comprises analkanoic carboxylic acid having from 5 to 35 carbon atoms.
 44. Atraceable treatment composition according to claim 42, wherein theorganic acid comprises an alkenoic carboxylic acid having from 5 to 30carbon atoms.
 45. A traceable treatment composition according to claim42, wherein the organic acid comprises a polyunsaturated aliphaticmonocarboxylic acid selected from the group consisting of sorbic acid,linoleic acid, linolenic acid and eleostearic acid.
 46. A traceabletreatment composition according to claim 42, wherein the organic acidcomprises an aromatic acid selected from the group consisting of benzoicacid, salicylic acid, cinnamic acid and gallic acid.
 47. A traceabletreatment composition according to claim 31, wherein the treatmentcomposition is a proppant composition comprising a particulate materialand a tracking material and wherein the tracking material is selectedfrom the group consisting of phosphorescent pigments, fluorescentpigments and photoluminescent pigments and wherein the phosphorescent,fluorescent, and photoluminescent pigments are prepared from materialsselected from the group consisting of alkaline earth aluminatesactivated by rare earth ions, zinc sulfide phosphors, aluminatephosphors, zinc silicate phosphors, zinc sulfide cadmium phosphors,strontium sulfide phosphors, calcium tungstate phosphors and calciumsulfide phosphors.